LOCATION AND REMOVAL OF DESLORELIN ACETATE IMPLANTS IN FEMALE AFRICAN LIONS (PANTHERA LEO)

Abstract

Contraception is necessary to manage zoo animal populations and to be able to house animals in groups without producing additional unwanted offspring. In felids and canids, an association between exposure to progestins and the occurrence of endometrial and mammary gland pathology has been documented. Therefore, the Association of Zoos and Aquariums (AZA) Wildlife Contraceptive Center recommends the use of deslorelin acetate for long-term contraception in carnivores. Return to cyclicity after deslorelin treatment has been variable; some individuals show ovarian suppression for long periods after the expected end of the deslorelin efficacy. In an attempt to reduce the time to reversal, techniques to locate and remove previous implants are being developed. This report documents the successful implementation of high-frequency ultrasonography in lions (Panthera leo) to locate and direct surgical removal of multiple deslorelin implants placed at least 2 yr previously as well as the return of follicular activity in both females at 7 months post-removal of implants.

The past, present and future of hormonal contraceptive use in managed captive female tiger populations with a focus on the current use of deslorelin acetate

“…Most implants were placed in the manufacturer's recommended site, between the scapulae (Cowl et al, 2018;Fontaine, 2015), and notably, no implants were removed in animals given a breeding opportunity. Extended periods of reproductive suppression with DA use and long times to reconception have previously been described in domestic and exotic felids (Bertschinger et al, 2008;Cowl et al, 2018;Fontaine, 2015;Goericke-Pesch, 2017;Moresco et al, 2014;Putman et al, 2015). This study did not find an association between implant removal and time to partial reversal and low rates of implant removal were identified.…”

“…Stimulation may be followed by a nonpregnant luteal phase or sustained progesterone elevation which could promote uterine pathology (Asa et al, 2012). In females, the DAinduced estrus can be suppressed by prophylactic treatment with oral megestrol acetate (MA), a short-acting progestagen (Asa et al, 2012(Asa et al, , 2014Moresco et al, 2014;Penfold et al, 2014). Other oral progestins (such as altrenogest) are also capable of suppressing ovulation in the cat (Stewart et al, 2010).…”

“…The lack of association between variables such as implant removal and full or partial reversals in this study may also, in part, be because of the small sample size available for analysis, highlighting the need for more complete and comprehensive data collection across zoological institutions. Previous studies have demonstrated that physical removal of both MGA and DA implants are associated with a faster return to reproductive cyclicity and fertility in exotic felids than leaving the implant in place to expire (Chuei et al, 2007;Moresco et al, 2014).…”

A role for selective contraception of individuals in conservation

“…A contraceptive is reversible either if it is removable (Moresco et al. ) or if breeding is successfully recommenced once the contraceptive effect wears off. Contraceptive longevity (and hence reversibility) varies within and between species and with the type of contraceptive agent (Asa et al.…”

“…This gives managers the flexibility to allow subsequent breeding of the animal if genetically (or numerically) desirable or the option to reapply fertility control if breeding remains undesirable. A contraceptive is reversible either if it is removable (Moresco et al 2014) or if breeding is successfully recommenced once the contraceptive effect wears off. Contraceptive longevity (and hence reversibility) varies within and between species and with the type of contraceptive agent ; AZA RMG 2016) (Table 1).…”